Every year in Australia over 7,000 women are diagnosed with bowel cancer – equal to 1 in 7 women developing the disease in their lifetime, writes medical researcher and female health advocate, Dr. Emily Handley.
What is bowel cancer?
The bowel is part of our digestive systems, made up of the small bowel – the small intestine – and the large bowel, encompassing the colon and the rectum. Bowel cancer is much more likely to develop in the large bowel, leading to bowel cancer also being commonly referred to as colorectal cancer.
The cancer develops from the inner lining of the bowel, and can be preceded by small tissue growths called polyps. When these polyps are left to grow undetected and unchecked, they precede or become an invasive cancer. The severity of bowel cancer is measured in stages known as the ‘TNM system’ – standing for Tumour, Nodes and Metastases.
The tumour stage measures how far a tumour-like growth has grown through the bowel wall. A score of one indicates the tumour is still in the inner layer of the bowel, while a score 4 indicates it has grown through and past the outer lining. The nodes stage covers whether the cancer has also spread to nearby lymph nodes; where a score of 0 means that the lymph nodes contain no cancer cells, while a score 2 reflects cancer cells in four or more lymph nodes.
Finally, metastases staging measures whether the cancer has spread around the body. This is a simple yes or no; 0 means that the cancer has not metastasised, while a score 1 means that the cancer has spread. Using these staging methods, a person diagnosed with bowel cancer is given a staging report that may look like ‘T2N1M0’. Additionally, the report may also have a lowercase letter added, where ‘c’ means the report is based on clinical scans and biopsies, while ‘p’ means it is based on the findings of pre-treatment investigation and pathological assessment after surgery.
The information from the TNM staging then is used to give an overall stage to the cancer from 1 to 4. Stage 1 indicates the cancer is contained within the bowel; stage 2 indicates the cancer has grown into or through the outer bowel wall; stage three indicates the cancer has spread to the lymph nodes; and stage 4 indicates that the cancer has spread to other parts of the body.
Bowel cancer – when caught at early stages – is easily treatable with a high survival rate. Yet symptoms can often be ignored or unspoken due to symptom embarrassment or confusion with other conditions.
Symptoms of bowel cancer
Bowel cancer presents with the similar symptoms in most people – but it is important to keep in mind that there are those who will experience no clear symptoms. The only clear way to determine if someone has bowel cancer is to get a screening. Though treatment is much more successful at the early stages of disease, it is not always easy to spot symptoms at this disease stage.
Two of the common symptoms of early-stage bowel cancer are long-lasting changes to bowel habits, and changes to the consistency of bowel movements. Sometimes, these primary symptoms can be accompanied by fatigue; weight loss; rectal or abdominal pain; and changes to the colour of stools. In later stages of the disease, symptoms are usually much more obvious and include long-term changes to bowel movements; bloating or pain the abdomen; and blood after bowel movements. Other symptoms – less common, though still reported – are the consistent urge to pass bowel movements; rectal bleeding; anaemia; excessive fatigue and weakness; as well as weight loss. When bowel cancer has spread, another whole suite of symptoms have to be accommodated for, depending on where in the body it has metastasised.
Keep in mind that many of the primary symptoms of bowel cancer can be easily confused for other diseases. When experiencing any of the symptoms above on their own, it’s likely that they are unrelated to a cancer diagnosis. However, when experiencing one or more at the same time, time is of the essence. If you recognise any of the above symptoms in yourself, speak to your doctor as soon as possible. It is also useful to begin keeping a symptom diary that you can present to your GP and reflect on to track changes that may be related to a cancer diagnosis.
If these symptoms cause your GP concern, you may then undergo a series of tests to determine whether there is a cancer present and what staging it is at. This can a blood test; an iFOBT or immunochemical faecal occult blood test, testing a stool sample; or various scanning techniques to see a potential stumour, such as MRI, CT or PET scans. However, the best test for bowel cancer is colonoscopy – this examines the length of the large bowel. During this procedure, air is pumped into the colon via a flexible tube inserted into the anus. A camera at the tip of the tube then allows the practitioner to search for abnormal tissues that can be examined.
A diagnosis of bowel cancer can be shocking, leaving the person anxious and confused. Yet for most, the disease is highly treatable and does not need to interfere with normal everyday activities.
Risk factors of bowel cancer
The exact causes of bowel cancer are still unknown, though we do have some clear risk factors that increase the chance of developing the disease. Some of these are unalterable – such as age and genetics – but there are risk factors linked to lifestyle that you can take control over to reduce your risk of developing bowel cancer.
Age is the most potent risk factor of developing the disease. Bowel cancer is much more likely to be diagnosed in those over the age of 50, and over half of all patients are 70 and older. Your personal and family history is another strong indicator; if you’ve had benign bowel polyps previously, you’re at increased risk of developing cancerous polyps later. This risk is increased if there is a history of polyps or bowel cancer in your family, which might indicate a genetic component. Specific genetic syndromes can also increase your risk of bowel cancer. These syndromes – such as familial adenomatous polyposis and Lynch syndrome – not only increase the risk of developing bowel cancer; they also predispose the person to develop polyps and cancerous growths at a much younger age. Finally, chronic diseases such as Crohn’s disease or being diagnosed with type 2 diabetes increase risk of bowel cancer. While these factors are not preventable, there are lifestyle interventions you can implement to mitigate your risk.
Lifestyle factors that increase your risk of developing bowel cancer are unsurprising: drinking alcohol, smoking, obesity, a poor diet, and a sedentary lifestyle are the usual suspects here. In terms of diet it is best to avoid processed meats and to limit red meats, instead eating plenty of whole fibre from grains, fruits and vegetables. It is estimated that 6% of bowel cancer diagnoses are linked to alcohol consumption, with 7% linked to tobacco smoking – and the risk of a bowel cancer diagnosis increases with the number of cigarettes smoked in a day.
Currently, there is tentative evidence that long-term use of aspirin may reduce the risk of both non-cancerous polyp growth and bowel cancer. Though it does come with side effects such as indigestion or bleeding, and it not yet known how safe it is to take it regularly. Studies do show that those taking aspirin for more than three years reduces the risk of bowel cancer, and can benefit those with a bowel cancer diagnosis. We still need more information as to how aspirin works in the body to combat bowel cancer, and with a risk of side effects, it’s critical to speak with a cancer specialist before embarking on long-term aspirin use.
The impacts of bowel cancer on women
While the symptoms and risk factors for bowel cancer aren’t vastly different between the sexes, women experience unique circumstances that impact the experience and diagnosis of bowel cancer.
Remember, the symptoms of bowel cancer can be mistaken for certain gynaecological conditions. Bloating, cramping and fatigue are associated with early symptoms of bowel cancer, but are also common appearances during the menstrual cycle. Weakness and fatigue associated with changes in bowel movements and abdominal pains are also relegated to menstrual pains, or to pre-menopausal fluctuations.
It’s not only symptom manifestation that is affected by the overlap between hormone cycles and conditions with bowel cancer. Women who have a history of endometrium cancer have an increased risk of developing bowel cancer, as do those carrying the MMR gene. Vice versa: one quarter of women who have been diagnosed with bowel cancer will also develop endometrium cancer, particularly in those with the MMR gene. Mutations in the MMR gene are linked to Lynch syndrome, where bowel cancer is one of the predominant diseases of the syndrome alongside with ovarian cancer. While men and women are affected equally by Lynch syndrome and MMR mutations, women are more likely to experience co-morbidity of cancers of the bowel and the endometrium or ovaries. In severe cases, the potential co-occurrence of bowel and ovarian or endometrium cancer can only be mitigated by hysterectomy.
Interestingly, oral contraceptives and hormone therapy might actually reduce the risk of developing bowel cancer. Oral contraceptives are associated with a 15-20% reduced risk of bowel cancer developing. Researchers have proposed that this may be due to lowering the levels of bile acids, increased levels of which are associated with cancerous polyp growth. And while hormone therapies have previously been linked with breast cancer development, they’ve been found to lower the risk of not only developing bowel cancer, but also mortality from the disease and reoccurrence of cancer in survivors
Treatments for bowel cancer often come with fertility risks for women of childbearing age. If the uterus is included in the field of radiation treating a bowl cancer, it can be damaged and make it difficult for a woman to successfully carry a pregnancy. In women who are pregnant, a bowel cancer diagnosis – though very rare – usually comes at a late stage in the disease development – with the experience of pregnancy overlapping the early symptoms of bowel cancer. Additionally, when these symptoms present doctors may hesitate to perform diagnostic tests, due to potential risk to the foetus and the younger age of the diagnosed person. Yet the exact reasons why bowel cancer is identified at late stages during pregnancy is still unclear – due to the increase in doctors visit and abdominal check-ups, it’s surprising that this is the case. In particularly, there are two enzymes that have been implicated in the development of cancer in the bowel – cyclocoxygenase 2 (Cox-2) and tumour suppressor protein p53.
Treatment and prevention
In the early stages of bowel cancer, the primary treatment is surgery to remove the cancerous tissue and polyps. Most commonly, a colectomy is performed, where part or all of the colon is removed. Systemic therapies – administered via intravenous drip – are also common treatment methods. The most common of these, chemotherapy, kills cancer cells, and this method is recommended if the cancer has reach the lymph nodes. Occasionally, chemotherapy will be used prior to surgery to ensure complete cancer removal. Radiation therapy is also often used prior to surgery, or in combination with chemotherapy, to reduce the number and the size of cancerous cells and tissues. Palliative care may also be discussed; where the goal is to slow the spread of cancer and relieve pain and discomfort of symptoms, without the goal of curing the disease.
All of these treatments come with side effects that vary from person to person. After surgery to treat bowel cancer, a survivor may be left with a permanent or temporary stoma. This is where part of the bowel pokes outside of the stomach, and while the thought may not be the most pleasant, those who have a stoma do not have a greatly impacted quality of life. The side effects of various therapies can also result in vomiting; hair loss; mouth and taste problems; changes to memory and sexual function; and exhaustion. The majority of these will be temporary, and when diagnosed with bowel cancer you will have a treatment team to guide you through managing these side-effects as well as the cancer symptoms.
Outlook
A bowel cancer diagnosis and subsequent treatments can have large impacts on both the physical and mental components of overall well-being. There’s often embarrassment around changes in bowel habits, particularly after surgery, as well as adjusting to stomas and scars. The mental impacts of these changes are just as important to your doctor as the physical aspects.
It is a common misconception that bowel cancer is a disease for old men only; yet it affects people of all ages, and women are as equally affected as men. Women face different challenges to men when it comes to a bowel cancer diagnosis and disease progression, and it is critical to discuss these with your healthcare team. Bowel cancer is highly treatable when detected early, highlighting just how important it is to feel comfortable having open and honest discussions around any possible symptoms with your health care provider.
Disclaimer: This article provides general information only, and does not constitute health or medical advice. If you have any concerns regarding your health, seek immediate medical attention.
